The present invention relates generally to control systems for printing presses and, more particularly, to printing press control systems which automatically identify which one of a plurality of webs is running through any one of a plurality of compensators.
Continuous web printing presses, such as high speed, high volume rotary presses used, for example, to print newspapers and the like, generally have a plurality of paper webs. These plurality of webs are supplied from a plurality of separate printing units, are superimposed on one another and are sent to a single folding/cutting mechanism. Each printing unit has at least one plate cylinder and at least one blanket cylinder for printing on a web. Each printing unit also has numerous other running cylinders and rollers for threading the web through the printing unit and the folding/cutting mechanism. It is necessary that the cutter mechanism cut the webs at imaginary page boundary lines between the adjacent pages as printed on the web. In known rotary printing presses, the cutter mechanism is stationary with respect to the cylinders that print the image on each web, and the proper cut-off registration is achieved by adjusting each web path length via one or more compensators.
A computerized control system controls the path length of each web by activating the appropriate compensator. Operating characteristics of the printing units and webs are used by the control system to regulate the compensators, such as web speed, thickness of the web and the like. Sensors mounted on the press monitor these operating characteristics and provide the information to the control system. Unfortunately, current control systems in printing presses are unable to automatically identify which web is running through which compensator. Press operators consequently must manually provide this information prior to starting the press.
Accordingly, there is a need in the art for a control system for a printing press having a plurality of webs and compensators for regulating the path lengths of the webs which automatically identifies which one of the webs is running through any one of the compensators.